• Title, Summary, Keyword: Dead time

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Online Dead Time Effect Compensation Algorithm of PWM Inverter for Motor Drive Using PR Controller

  • Park, Chang-Seok;Jung, Tae-Uk
    • Journal of Electrical Engineering and Technology
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    • v.12 no.3
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    • pp.1137-1145
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    • 2017
  • This paper proposes the dead time effect compensation algorithm using proportional resonant controller in pulse width modulation inverter of motor drive. To avoid a short circuit in the dc link, the dead time of the switch device is surely required. However, the dead time effect causes the phase current distortions, torque pulsations, and degradations of control performance. To solve these problems, the output current including ripple components on the synchronous reference frame and stationary reference frame are analyzed in detail. As a results, the distorted synchronous d-and q-axis currents contain the 6th, 12th, and the higher harmonic components due to the influence of dead time effect. In this paper, a new dead time effect compensation algorithm using proportional resonant controller is also proposed to reduce the output current harmonics due to the dead time and nonlinear characteristics of the switching devices. The proposed compensation algorithm does not require any additional hardware and the offline experimental measurements. The experimental results are presented to demonstrate the effectiveness of the proposed dead time effect compensation algorithm.

A New Switching Strategy for The Output Current Control of Inverters (인버터 출력 전류제어를 위한 새로운 스위칭 방법)

  • In, Chi-Gak;Oh, Won-Seok;Cho, Kyu-Min;You, Wan-Sik
    • Proceedings of the KIEE Conference
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    • pp.375-377
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    • 1999
  • It is necessary to obtain the high performance of the inverter system that control the output current of inverters. The dead time causes detrimental effects to the control performance of the inverter system. So we need to compensate the dead time effects. And the dead time minimization switching method can be considered as the best way to avoid the dead time effects fundamentally. In this paper, a new dead time minimization switching strategy is proposed. According to the proposed method, very short dead time is adopted in only once when the current polarity is changing. And the adopted dead time is equal to the applied dead time or shorter than it. As the proposed method can be done with the porlarity information of the reference current. it is easy to avoid some problems in comparison with the case that the real current is used to get the polarity changing time; level detection difficulty, noise problem and so on.

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Compensation of Dead-Time in PWM Voltage Inverters

  • Somchaiwong, Nitipong;Chaidee, Ekkachai
    • 제어로봇시스템학회:학술대회논문집
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    • pp.817-820
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    • 2005
  • Dead-Time is necessary to prevent the shot circuit of the full bridge inverters in pulse width modulation. However the output voltage deviations is the result of the Dead-Time that decrease power from the out put voltage inverters. This paper presents the method that compensate power output voltage inverters loss in Dead-Time circuit for DC Motor Drives with full bridge voltage inverters. The compensation of Dead-Time method is a sample and a low-cost solution. The comparison between the test results and simulation by MATLAB&SIMULINK under the same condition is similar.

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Dead Time Compensation Scheme Independent of Parameter Variations in an Inverter-fed PMSM Drive (파라미터 변화에 무관한 인버터 구동 PMSM의 데드타임 보상 기법)

  • Kim, Kyeong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.4
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    • pp.124-134
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    • 2011
  • A new dead time compensation scheme that can exactly estimate the dead time and inverter nonlinearity under parameter variations is proposed for a PWM inverter-fed PMSM drive. The proposed scheme uses the fact that the sixth harmonic component in total disturbance estimated under the presence of various uncertainties is mainly caused by the dead time and inverter nonlinearity. The total disturbance due to the parameter variations as well as the dead time and inverter nonlinearity is estimated by the adaptive scheme. The sixth harmonic component is extracted from this total disturbance through harmonic analysis. The obtained sixth harmonic is processed by the PI controller to estimate the disturbance caused by the dead time and inverter nonlinearity in the stationary reference frame. The effectiveness of the proposed scheme is verified. Without requiring an additional hardware, the proposed scheme can effectively compensate the dead time and inverter nonlinearity even under the parameter variations.

Analysis and Compensation Control of Dead-Time Effect on Space Vector PWM

  • Shi, Jie;Li, Shihua
    • Journal of Power Electronics
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    • v.15 no.2
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    • pp.431-442
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    • 2015
  • Dead-time element must be set into space vector pulsed width modulation signals to avoid short circuits of the inverter. However, the dead-time element distorts the output voltage vector, which deteriorates the performance of electrical machine drive system. In this paper, dead-time effect and its compensation control strategy are analyzed. Based on the analysis, the voltage distortion caused by dead-time is regarded as two disturbances imposed on dq axes in the rotor reference frame, which degenerates the current tracking performance. To inhibit the adverse effect caused by the dead-time, a control scheme using two linear extended state observers is proposed. This method provides a strong ability to suppress dead-time effects. Simulations and experiments are conducted on a permanent magnet synchronous motor drive system to demonstrate the effectiveness of the proposed method.

Dead time Compensation of Single-phase Grid-connected Inverter Using SOGI (SOGI를 이용한 단상 계통연계형 인버터의 데드타임 보상)

  • Seong, Ui-Seok;Lee, Jae-Suk;Hwang, Seon-Hwan;Kim, Jang-Mok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.2
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    • pp.166-174
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    • 2017
  • This study proposes a compensation method for the dead-time effects on a single-phase grid-connected inverter. Dead time should be considered in the pulse-width modulation gating signals to prevent the simultaneous conduction of switching devices, considering that a switching device has a finite switching time. Consequently, the output current of the grid-connected inverter contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. The effects of dead time on output voltage and current are analyzed in this study. A new compensation algorithm based on second-order generalized integrator is also proposed to reduce the dead-time effect. Simulation and experimental results validate the effectiveness of the proposed compensation algorithm.

A New On-Line Dead-Time Compensator for Single-Phase PV Inverter (단상 PV 인버터용 온라인 데드타임 보상기 연구)

  • Vu, Trung-Kien;Lee, Sang-Hoey;Cha, Han-Ju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.5
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    • pp.409-415
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    • 2012
  • This paper presents a new software-based on-line dead-time compensation technique for a single-phase grid-connected photovoltaic (PV) inverter system. To prevent a short circuit in the inverter arms, a switching delay time must be inserted in the pulse width modulation (PWM) signals. This causes the dead-time effect, which degrades the system performance around zero-crossing point of the output current. To reduce the dead-time effect around the zero-crossing point of grid current, a harmonic mitigation of grid current is used as an additional part of the synchronous frame current control scheme. This additional task mitigates the harmonic components caused by the dead-time from the grid current. Simulation and experimental results are shown to verify the effectiveness of the proposed dead-time compensation method in the single-phase grid-connected inverter system.

A Study on the Space Vector PWM Inverter without Dead Time (데드 타임 없는 공간 벡터 전압 변조 인버터에 관한 연구)

  • Seo Il-Soo;Song Eui-Ho
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.1
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    • pp.38-44
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    • 2005
  • In a voltage source inverter, the dead time is necessary to prevent short circuits in the dc link. The dead time effect appears as a distortion of output voltages and currents. In recent years, the dead time compensation methods have been investigated in many literatures. This paper presents not the dead time compensation by sensing and calculation but the dead time elimination. The proposed inverter system doesn't need to sense load current and to calculate dead time. Adding some transformers to each leg, dead times in the inverter system are eliminated automatically. The proposed method is analyzed on each mode and verified through simulation results.

New Approach Using the Continued Fraction Expansion for the Dead Time Approximation (Continued Fraction Expansion을 이용한 Dead Time 근사의 새로운 접근)

  • Cho, Won-Hui;Lee, Jie-Tae
    • Korean Chemical Engineering Research
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    • v.50 no.5
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    • pp.830-836
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    • 2012
  • Dead times appear often in describing process dynamics and raise some difficulties in simulating process dynamics or analyzing process control systems. To relieve these difficulties, it is needed to approximate the infinite dimensional dead time by the finite dimensional transfer function and, for this, the Pade approximation method is often used. For the accurate approximation of the dead time, high order Pade approximation is needed and the high order Pade approximation is not easy to memorize and is not stable numerically. We propose a method based on the continued fraction expansion that provides the same transfer functions. The method is excellent numerically as well as systematic to be memorized easily. It can be used conveniently for the process control lecture and computations.

High rate diffusion-scale approximation for counters with extendable dead time

  • Dubi, Chen;Atar, Rami
    • Nuclear Engineering and Technology
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    • v.51 no.6
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    • pp.1616-1625
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    • 2019
  • Measuring occurrence times of random events, aimed to determine the statistical properties of the governing stochastic process, is a basic topic in science and engineering, and has been the subject of numerous mathematical modeling approaches. Often, true statistical properties deviate from measured properties due to the so called dead time phenomenon, where for a certain time period following detection, the detection system is not operational. Understanding the dead time effect is especially important in radiation measurements, often characterized by high count rates and a non-reducible detector dead time (originating in the physics of particle detection). The effect of dead time can be interpreted as a suitable rarefied sequence of the original time sequence. This paper provides a limit theorem for a high rate (diffusion-scale) counter with extendable (Type II) dead time, where the underlying counting process is a renewal process with finite second moment for the inter-event distribution. The results are very general, in the sense that they refer to a general inter arrival time and a random dead time with general distribution. Following the theoretical results, we will demonstrate the applicability of the results in three applications: serially connected components, multiplicity counting and measurements of aerosol spatial distribution.